Index: Ringtoets/DuneErosion/test/Ringtoets.DuneErosion.Forms.Test/Views/DuneErosionSectionResultRowTest.cs
===================================================================
diff -u -r34b717d20885d69c8de8f5c3ad5f18851fe0ffaf -r4dbb8c9e658bb02d5f1ff5aaf5dc3b45fc1c47ac
--- Ringtoets/DuneErosion/test/Ringtoets.DuneErosion.Forms.Test/Views/DuneErosionSectionResultRowTest.cs	(.../DuneErosionSectionResultRowTest.cs)	(revision 34b717d20885d69c8de8f5c3ad5f18851fe0ffaf)
+++ Ringtoets/DuneErosion/test/Ringtoets.DuneErosion.Forms.Test/Views/DuneErosionSectionResultRowTest.cs	(.../DuneErosionSectionResultRowTest.cs)	(revision 4dbb8c9e658bb02d5f1ff5aaf5dc3b45fc1c47ac)
@@ -159,6 +159,33 @@
         }
 
         [Test]
+        public void Constructor_AssemblyThrowsException_ExpectedColumnStates()
+        {
+            // Setup
+            FailureMechanismSection section = FailureMechanismSectionTestFactory.CreateFailureMechanismSection();
+            var result = new DuneErosionFailureMechanismSectionResult(section);
+
+            using (new AssemblyToolCalculatorFactoryConfig())
+            {
+                var calculatorfactory = (TestAssemblyToolCalculatorFactory) AssemblyToolCalculatorFactory.Instance;
+                FailureMechanismSectionAssemblyCalculatorStub calculator = calculatorfactory.LastCreatedFailureMechanismSectionAssemblyCalculator;
+                calculator.ThrowExceptionOnCalculate = true;
+
+                // Call
+                var row = new DuneErosionSectionResultRow(result, ConstructionProperties);
+
+                // Assert
+                IDictionary<int, DataGridViewColumnStateDefinition> columnStateDefinitions = row.ColumnStateDefinitions;
+                const string expectedErrorText = "Message";
+
+                Assert.AreEqual(expectedErrorText, columnStateDefinitions[ConstructionProperties.SimpleAssemblyCategoryGroupIndex].ErrorText);
+                Assert.AreEqual(expectedErrorText, columnStateDefinitions[ConstructionProperties.DetailedAssemblyCategoryGroupIndex].ErrorText);
+                Assert.AreEqual(expectedErrorText, columnStateDefinitions[ConstructionProperties.TailorMadeAssemblyCategoryGroupIndex].ErrorText);
+                Assert.AreEqual(expectedErrorText, columnStateDefinitions[ConstructionProperties.CombinedAssemblyCategoryGroupIndex].ErrorText);
+            }
+        }
+
+        [Test]
         public void UseManualAssemblyCategoryGroup_SetNewValue_NotifyObserversAndPropertyChanged()
         {
             // Setup
Index: Ringtoets/Integration/src/Ringtoets.Integration.Forms/Views/SectionResultRows/GrassCoverSlipOffOutwardsSectionResultRow.cs
===================================================================
diff -u -rf2cb20c760b6830245f781b0527fff6f6a6e8795 -r4dbb8c9e658bb02d5f1ff5aaf5dc3b45fc1c47ac
--- Ringtoets/Integration/src/Ringtoets.Integration.Forms/Views/SectionResultRows/GrassCoverSlipOffOutwardsSectionResultRow.cs	(.../GrassCoverSlipOffOutwardsSectionResultRow.cs)	(revision f2cb20c760b6830245f781b0527fff6f6a6e8795)
+++ Ringtoets/Integration/src/Ringtoets.Integration.Forms/Views/SectionResultRows/GrassCoverSlipOffOutwardsSectionResultRow.cs	(.../GrassCoverSlipOffOutwardsSectionResultRow.cs)	(revision 4dbb8c9e658bb02d5f1ff5aaf5dc3b45fc1c47ac)
@@ -252,12 +252,21 @@
 
         private void UpdateDerivedData()
         {
+            ResetErrorTexts();
             TryGetSimpleAssemblyCategoryGroup();
             TryGetDetailedAssemblyCategoryGroup();
             TryGetTailorMadeAssemblyCategoryGroup();
             TryGetCombinedAssemblyCategoryGroup();
         }
 
+        private void ResetErrorTexts()
+        {
+            ColumnStateDefinitions[simpleAssemblyCategoryGroupIndex].ErrorText = string.Empty;
+            ColumnStateDefinitions[detailedAssemblyCategoryGroupIndex].ErrorText = string.Empty;
+            ColumnStateDefinitions[tailorMadeAssemblyCategoryGroupIndex].ErrorText = string.Empty;
+            ColumnStateDefinitions[combinedAssemblyCategoryGroupIndex].ErrorText = string.Empty;
+        }
+
         private void TryGetSimpleAssemblyCategoryGroup()
         {
             try
@@ -267,6 +276,7 @@
             catch (AssemblyException e)
             {
                 simpleAssemblyCategoryGroup = FailureMechanismSectionAssemblyCategoryGroup.None;
+                ColumnStateDefinitions[simpleAssemblyCategoryGroupIndex].ErrorText = e.Message;
             }
         }
 
@@ -279,6 +289,7 @@
             catch (AssemblyException e)
             {
                 detailedAssemblyCategoryGroup = FailureMechanismSectionAssemblyCategoryGroup.None;
+                ColumnStateDefinitions[detailedAssemblyCategoryGroupIndex].ErrorText = e.Message;
             }
         }
 
@@ -291,6 +302,7 @@
             catch (AssemblyException e)
             {
                 tailorMadeAssemblyCategoryGroup = FailureMechanismSectionAssemblyCategoryGroup.None;
+                ColumnStateDefinitions[tailorMadeAssemblyCategoryGroupIndex].ErrorText = e.Message;
             }
         }
 
@@ -303,6 +315,7 @@
             catch (AssemblyException e)
             {
                 combinedAssemblyCategoryGroup = FailureMechanismSectionAssemblyCategoryGroup.None;
+                ColumnStateDefinitions[combinedAssemblyCategoryGroupIndex].ErrorText = e.Message;
             }
         }
 
Index: Ringtoets/Integration/test/Ringtoets.Integration.Forms.Test/Views/SectionResultRows/GrassCoverSlipOffOutwardsSectionResultRowTest.cs
===================================================================
diff -u -rf2cb20c760b6830245f781b0527fff6f6a6e8795 -r4dbb8c9e658bb02d5f1ff5aaf5dc3b45fc1c47ac
--- Ringtoets/Integration/test/Ringtoets.Integration.Forms.Test/Views/SectionResultRows/GrassCoverSlipOffOutwardsSectionResultRowTest.cs	(.../GrassCoverSlipOffOutwardsSectionResultRowTest.cs)	(revision f2cb20c760b6830245f781b0527fff6f6a6e8795)
+++ Ringtoets/Integration/test/Ringtoets.Integration.Forms.Test/Views/SectionResultRows/GrassCoverSlipOffOutwardsSectionResultRowTest.cs	(.../GrassCoverSlipOffOutwardsSectionResultRowTest.cs)	(revision 4dbb8c9e658bb02d5f1ff5aaf5dc3b45fc1c47ac)
@@ -147,6 +147,33 @@
         }
 
         [Test]
+        public void Constructor_AssemblyThrowsException_ExpectedColumnStates()
+        {
+            // Setup
+            FailureMechanismSection section = FailureMechanismSectionTestFactory.CreateFailureMechanismSection();
+            var result = new GrassCoverSlipOffOutwardsFailureMechanismSectionResult(section);
+
+            using (new AssemblyToolCalculatorFactoryConfig())
+            {
+                var calculatorfactory = (TestAssemblyToolCalculatorFactory) AssemblyToolCalculatorFactory.Instance;
+                FailureMechanismSectionAssemblyCalculatorStub calculator = calculatorfactory.LastCreatedFailureMechanismSectionAssemblyCalculator;
+                calculator.ThrowExceptionOnCalculate = true;
+
+                // Call
+                var row = new GrassCoverSlipOffOutwardsSectionResultRow(result, ConstructionProperties);
+
+                // Assert
+                IDictionary<int, DataGridViewColumnStateDefinition> columnStateDefinitions = row.ColumnStateDefinitions;
+                const string expectedErrorText = "Message";
+
+                Assert.AreEqual(expectedErrorText, columnStateDefinitions[ConstructionProperties.SimpleAssemblyCategoryGroupIndex].ErrorText);
+                Assert.AreEqual(expectedErrorText, columnStateDefinitions[ConstructionProperties.DetailedAssemblyCategoryGroupIndex].ErrorText);
+                Assert.AreEqual(expectedErrorText, columnStateDefinitions[ConstructionProperties.TailorMadeAssemblyCategoryGroupIndex].ErrorText);
+                Assert.AreEqual(expectedErrorText, columnStateDefinitions[ConstructionProperties.CombinedAssemblyCategoryGroupIndex].ErrorText);
+            }
+        }
+
+        [Test]
         public void UseManualAssemblyCategoryGroup_SetNewValue_NotifyObserversAndPropertyChanged()
         {
             // Setup
@@ -207,6 +234,86 @@
             }
         }
 
+        [Test]
+        public void GivenRowWithoutAssemblyErrors_WhenUpdatingAndAssemblyThrowsException_ThenAssemblyGroupSetToNone()
+        {
+            // Given
+            var random = new Random(39);
+            FailureMechanismSection section = FailureMechanismSectionTestFactory.CreateFailureMechanismSection();
+            var result = new GrassCoverSlipOffOutwardsFailureMechanismSectionResult(section);
+
+            using (new AssemblyToolCalculatorFactoryConfig())
+            {
+                var calculatorfactory = (TestAssemblyToolCalculatorFactory) AssemblyToolCalculatorFactory.Instance;
+                FailureMechanismSectionAssemblyCalculatorStub calculator = calculatorfactory.LastCreatedFailureMechanismSectionAssemblyCalculator;
+                calculator.SimpleAssessmentAssemblyOutput = new FailureMechanismSectionAssembly(
+                    random.NextDouble(),
+                    random.NextEnumValue<FailureMechanismSectionAssemblyCategoryGroup>());
+                calculator.DetailedAssessmentAssemblyGroupOutput = random.NextEnumValue<FailureMechanismSectionAssemblyCategoryGroup>();
+                calculator.TailorMadeAssemblyCategoryOutput = random.NextEnumValue<FailureMechanismSectionAssemblyCategoryGroup>();
+                calculator.CombinedAssemblyCategoryOutput = random.NextEnumValue<FailureMechanismSectionAssemblyCategoryGroup>();
+
+                var row = new GrassCoverSlipOffOutwardsSectionResultRow(result, ConstructionProperties);
+
+                // Precondition
+                Assert.AreEqual(FailureMechanismSectionResultRowHelper.GetCategoryGroupDisplayname(calculator.SimpleAssessmentAssemblyOutput.Group),
+                                row.SimpleAssemblyCategoryGroup);
+                Assert.AreEqual(FailureMechanismSectionResultRowHelper.GetCategoryGroupDisplayname(calculator.DetailedAssessmentAssemblyGroupOutput.Value),
+                                row.DetailedAssemblyCategoryGroup);
+                Assert.AreEqual(FailureMechanismSectionResultRowHelper.GetCategoryGroupDisplayname(calculator.TailorMadeAssemblyCategoryOutput.Value),
+                                row.TailorMadeAssemblyCategoryGroup);
+                Assert.AreEqual(FailureMechanismSectionResultRowHelper.GetCategoryGroupDisplayname(calculator.CombinedAssemblyCategoryOutput.Value),
+                                row.CombinedAssemblyCategoryGroup);
+
+                // When
+                calculator.ThrowExceptionOnCalculate = true;
+                row.SimpleAssessmentResult = SimpleAssessmentResultType.AssessFurther;
+
+                // Then
+                string expectedAssemblyDisplayName = FailureMechanismSectionResultRowHelper.GetCategoryGroupDisplayname(FailureMechanismSectionAssemblyCategoryGroup.None);
+                Assert.AreEqual(expectedAssemblyDisplayName, row.SimpleAssemblyCategoryGroup);
+                Assert.AreEqual(expectedAssemblyDisplayName, row.DetailedAssemblyCategoryGroup);
+                Assert.AreEqual(expectedAssemblyDisplayName, row.TailorMadeAssemblyCategoryGroup);
+                Assert.AreEqual(expectedAssemblyDisplayName, row.CombinedAssemblyCategoryGroup);
+            }
+        }
+
+        [Test]
+        public void GivenRowWithAssemblyErrors_WhenUpdatingAndAssemblyDoesNotThrowException_ThenExpectedColumnStates()
+        {
+            // Given
+            FailureMechanismSection section = FailureMechanismSectionTestFactory.CreateFailureMechanismSection();
+            var result = new GrassCoverSlipOffOutwardsFailureMechanismSectionResult(section);
+
+            using (new AssemblyToolCalculatorFactoryConfig())
+            {
+                var calculatorfactory = (TestAssemblyToolCalculatorFactory) AssemblyToolCalculatorFactory.Instance;
+                FailureMechanismSectionAssemblyCalculatorStub calculator = calculatorfactory.LastCreatedFailureMechanismSectionAssemblyCalculator;
+                calculator.ThrowExceptionOnCalculate = true;
+
+                var row = new GrassCoverSlipOffOutwardsSectionResultRow(result, ConstructionProperties);
+
+                // Precondition
+                IDictionary<int, DataGridViewColumnStateDefinition> columnStateDefinitions = row.ColumnStateDefinitions;
+                const string expectedErrorText = "Message";
+
+                Assert.AreEqual(expectedErrorText, columnStateDefinitions[ConstructionProperties.SimpleAssemblyCategoryGroupIndex].ErrorText);
+                Assert.AreEqual(expectedErrorText, columnStateDefinitions[ConstructionProperties.DetailedAssemblyCategoryGroupIndex].ErrorText);
+                Assert.AreEqual(expectedErrorText, columnStateDefinitions[ConstructionProperties.TailorMadeAssemblyCategoryGroupIndex].ErrorText);
+                Assert.AreEqual(expectedErrorText, columnStateDefinitions[ConstructionProperties.CombinedAssemblyCategoryGroupIndex].ErrorText);
+
+                // When
+                calculator.ThrowExceptionOnCalculate = false;
+                row.SimpleAssessmentResult = SimpleAssessmentResultType.AssessFurther;
+
+                // Then
+                Assert.AreEqual(string.Empty, columnStateDefinitions[ConstructionProperties.SimpleAssemblyCategoryGroupIndex].ErrorText);
+                Assert.AreEqual(string.Empty, columnStateDefinitions[ConstructionProperties.DetailedAssemblyCategoryGroupIndex].ErrorText);
+                Assert.AreEqual(string.Empty, columnStateDefinitions[ConstructionProperties.TailorMadeAssemblyCategoryGroupIndex].ErrorText);
+                Assert.AreEqual(string.Empty, columnStateDefinitions[ConstructionProperties.CombinedAssemblyCategoryGroupIndex].ErrorText);
+            }
+        }
+
         #region Registration
 
         [Test]